Lava on location

While on holiday recently, I visited Big Island in Hawai'i to see the active volcanoes and lava flows. My interest was sparked by the exhibit in the Dynamic Earth exhibition at Melbourne Museum which includes a large sample of 'ropy lava' that visitors are invited to touch. The name describes the ribbed appearance of the lava that looks like a collection of ropes formed as the liquid lava cooled. The Hawaiian name for this form of lava is pahoehoe.

I visited the Kilauea volcano which is currently active. In the vast caldera is a crater holding a lava lake. Great quantities of volcanic gases rise from the lava lake and the orange glow from the molten lava is visible. It would be very dangerous to stand downwind of the vog (volcanic fog) as it contains large quantities of sulphur dioxide and other noxious gases.

Around the caldera are steam vents, where lava flowing through underground tubes heats rainwater seeping though the ground and turns it into steam. Visitors can walk through a large extinct lava tube.

I explored three lava flows that originated in the Mauna Ulu vent on the flank of Kilauea. It is essential to wear sturdy footwear and the tread very carefully, for a fall onto the abrasive, glassy surface can result in serious injury. Each flow was different in character as the mix of lava and gases and form of each eruption varies. The third lava field that I visited produced the most impressive ropey lava, with a smooth shiny surface that glistened in the sunlight. The stream of viscous lava had hardened where it had cooled leaving vivid evidence of the way in which it had flowed from the Mauna Ulu vent. It was fascinating to walk to the edge of the flow to see where the lava had stopped, leaving the trees and other vegetation untouched. Also interesting to see were plants that had managed to gain a foothold on the lava as recolonisation is taking place thirty or forty years after the eruption.